Bioaugmentation (site inoculation with a microbial culture) is a proven approach for stimulating complete dechlorination of sites contaminated with chlorinated ethenes. However, cultures have not been available for the large-scale treatment of chlorinated ethane contamination. Of additional concern, chlorinated ethanes can inhibit the degradation of chlorinated ethenes. Thus, cultures are needed for bioremediation of sites with mixtures of these contaminants.
Contamination of groundwater with chlorinated ethenes and ethanes is a serious problem due to widespread and historic commercial, industrial, and military use, relative resistance to degradation, and associated health hazards. Under anaerobic conditions, chlorinated ethenes and ethanes can be partially reduced to less chlorinated compounds or completely degraded to nonchlorinated end products depending on the physiological capability of an indigenous microbial community.
Bacterial isolates capable of reducing 1,2-dichloroethane (DCA) and 1,1,1-trichloroethane have been identified. One isolate has been shown to reduce 1,1,2,2-tetrachloroethane (TeCA) to cis 1,2-dichloroethene (cisDCE). Recent research on a mixed culture demonstrated growth of Dehalobacter sp. with the reduction of 1,1,2-trichloroethane (TCA) to vinyl chloride (VC). See Jones et al., Characterization of a Microbial Consortium Capable of Rapid and Simultaneous Dechlorination of 1,1,2,2-Tetrachloroethane and Chlorinated Ethane and Ethene Intermediates, Bioremediation Journal, 10:153-168 (2006), the disclosure of which is incorporated herein by reference in its entirety.